Atopic dermatitis is one of the chronic skin diseases, accompanied by dry skin, keratinization, itching, etc. 0.5 to 1% of the total populations, especially 5 to 10% of children, suffer from atopic dermatitis, and the patients thereof are increasing recently. In the sites affected by atopic dermatitis, the infiltration of immune-related cells, such as macrophages, mast cells, Th lymphocytes, etc., is significantly increased. The serum IgE level is highly increased in the atopic dermatitis patients, because the number of Th2 cells is increased and thus the Th2 cell-secreted cytokines such as IL-6 stimulate B lymphocytes, thereby promoting the IgE secretion. Therefore, atopic dermatitis is classified into a Th2-type skin disease, which is related to immune system abnormalities. Although atopic dermatitis causes a lot of economic damage along with physical and mental suffering to the patient, the specific remedy for treating atopic dermatitis was not yet reported. Drugs such as steroids, antihistamines, etc. are currently used as a therapeutic agent against atopic dermatitis. However, because the long-term use of these drugs induces serious side effects, there is a need for an alternative drug.
Cordyceps is one of the insect-parasitic fungi and belongs to the genus Cordyceps. It is known that about 300 species are currently distributed around the world. Cordyceps invades insect larvae, pupae, adults, etc., to kill the insect, and then forms fruit bodies and fruits using it as a host. Cordyceps, which has been known as a secret medicine for eternal youth and long life in China, is being widely used as an herbal medicine for the treatment of respiratory diseases such as asthma, hepatic disease such as jaundice, etc. Recently, extensive researches on the immune enhancing effect thereof are underway. There are literatures reporting that a C. sinensis extract, a C. militaris extract, and cordycepin (the major component of Cordyceps) function as an anti-inflammatory agent, in addition to as an immune regulator.
C. bassiana, a kind of Cordyceps, is an insect-parasitic fungus belonging to the order Lepidoptera. C. bassiana was firstly found in China and has been also found in Korea. Beauveria bassiana, one of the forms emerging during the life cycle of C. bassiana, has been used in the treatment of neurological disorders, cancer, skin infections, wounds, etc., from long time ago in China and Korea (Donguibogam). However, there has been no information on the efficacies of the fruit body of C. bassiana. 
Meanwhile, Korean patent no. 10-1013061 has disclosed that a C. bassiana extract is useful for preventing and treating skin itching and atopic dermatitis. And also, Korean patent no. 10-1079221 has disclosed an improved process for preparing a C. bassiana extract, the process of which involves hot-water extraction of C. bassiana. In addition, there have been disclosed an anti-atopic functional cosmetic soap composition, an anti-atopic functional cosmetic composition, an anti-atopic functional food composition, and an anti-atopic functional ice cream composition (Korean patent no. 10-1104408, Korean patent publication nos. 10-2010-0122356, 10-2010-0122357, and 10-2010-0122359).